Devices for controlling the flow rate in a control valve, in particularly, the flow control of water through household appliances, such as dishwashers, clothes washers, refrigerator ice makers and similar devices are well-known. In providing flow rate control to household appliances connected to municipal water supplies, it is desired to provide a generally constant flow rate to the appliance while minimizing the audible noise generated by the fluid flow therethrough. Various types of flow control devices have been employed for this purpose and a particular well-known device is an elastomeric washer which deforms resiliently under increasing supply pressure to restrict the flow orifice size thereby maintaining a constant flow rate therethrough.
However, in providing flow control to the water inlet of the appliance, problems have been experienced in excessive noise, where the restrictions of the flow control device have produced cavitation. In cases where the flow control is carried out adjacent an electrically operated water inlet valve, the noise problem has been particularly exacerbated by the flow cavitation causing resonant vibration of the surrounding valve body structure. This problem has been particularly troublesome in appliance water inlet valves having a body structure rigidedly secured to a surrounding metal frame or cabinet of the appliance.
Where an appliance water inlet flow control device is required to control substantial restriction to accommodate relatively high water supply pressures for maintaining a constant flow rate to the appliance inlet, severe high frequency vibration has been encountered as cavitation occurred at the flow control device and the resulting noise is perceived to be quite objectionable to the consumer.
In most fluid flow systems, the water held therein is eventually allowed to be discharged into a container or appliance and is selectively controlled by an electronically actuated valve. When opened, fluid flowing from a relatively high pressure source passes through an orifice to a low pressure region within the control valve. In doing so, a screech or similar noise is readily apparent as the valve is initially opened. Even the flow through piping once the valve is opened can generate an objectable noise. In the past, various means of designing the flow path through the control valve have been attempted to reduce the level of water expulsion noise so as to produce a quieter environment. Many of these solutions can be quite elaborate, sizable, or expensive.
With respect to the present invention, audible noise of fluid flowing through an electronically operated solenoid water dispensing valve can often times be annoying to the consumer. In this instance, water at a high pressure is contained and then upon the energization of the solenoid, an opening is attained wherein the water will expel to the lower pressure region. In the past, efforts were made to redesign and curve the flow/path to reduce the water splash within the low pressure region, however, due to the high velocity of the fluid flowing through the control valve, such modifications rarely meet with success in reducing the audible noise generated by the flow of fluid through the valve.
In an effort to reduce the noise of fluid flowing through a conduit, U.S. Pat. No. 5,226,446 discloses a flow noise reduction assembly having a fixed flow limiting orifice or an inlet pressure responsive flow control washer having a flow limiting orifice. In either manner, a conically faced diverter is disposed closely adjacent to the down stream face of the orifice and an expansion chamber is disposed down stream of the flow diverter for noise attenuation. Therein, fluid flowing through the conduit and the flow limiting orifice is diverted by a restriction in the flow path in order to disperse fluid flowing through the orifice into an expansion chamber immediately adjacent the down stream face of the orifice. The diverter is positioned in the flow stream and connected to an outer rim by spaced radially spokes which over time will wear requiring the diverter to be maintained and serviced on a regular basis.
Therefore, there is clearly a need for an inexpensive means for quieting the flow of fluid in a fluid dispenser adjacent a control valve with such means being inexpensive to incorporate into the existing supply valve or into new supply valves and which requires little if any maintenance over the life of the appliance.